xref: /openbmc/linux/fs/nfs/super.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
1 /*
2  *  linux/fs/nfs/super.c
3  *
4  *  Copyright (C) 1992  Rick Sladkey
5  *
6  *  nfs superblock handling functions
7  *
8  *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
9  *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
10  *
11  *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
12  *  J.S.Peatfield@damtp.cam.ac.uk
13  *
14  *  Split from inode.c by David Howells <dhowells@redhat.com>
15  *
16  * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
17  *   particular server are held in the same superblock
18  * - NFS superblocks can have several effective roots to the dentry tree
19  * - directory type roots are spliced into the tree when a path from one root reaches the root
20  *   of another (see nfs_lookup())
21  */
22 
23 #include <linux/module.h>
24 #include <linux/init.h>
25 
26 #include <linux/time.h>
27 #include <linux/kernel.h>
28 #include <linux/mm.h>
29 #include <linux/string.h>
30 #include <linux/stat.h>
31 #include <linux/errno.h>
32 #include <linux/unistd.h>
33 #include <linux/sunrpc/clnt.h>
34 #include <linux/sunrpc/stats.h>
35 #include <linux/sunrpc/metrics.h>
36 #include <linux/sunrpc/xprtsock.h>
37 #include <linux/sunrpc/xprtrdma.h>
38 #include <linux/nfs_fs.h>
39 #include <linux/nfs_mount.h>
40 #include <linux/nfs4_mount.h>
41 #include <linux/lockd/bind.h>
42 #include <linux/smp_lock.h>
43 #include <linux/seq_file.h>
44 #include <linux/mount.h>
45 #include <linux/nfs_idmap.h>
46 #include <linux/vfs.h>
47 #include <linux/inet.h>
48 #include <linux/in6.h>
49 #include <net/ipv6.h>
50 #include <linux/netdevice.h>
51 #include <linux/nfs_xdr.h>
52 #include <linux/magic.h>
53 #include <linux/parser.h>
54 
55 #include <asm/system.h>
56 #include <asm/uaccess.h>
57 
58 #include "nfs4_fs.h"
59 #include "callback.h"
60 #include "delegation.h"
61 #include "iostat.h"
62 #include "internal.h"
63 
64 #define NFSDBG_FACILITY		NFSDBG_VFS
65 
66 enum {
67 	/* Mount options that take no arguments */
68 	Opt_soft, Opt_hard,
69 	Opt_posix, Opt_noposix,
70 	Opt_cto, Opt_nocto,
71 	Opt_ac, Opt_noac,
72 	Opt_lock, Opt_nolock,
73 	Opt_v2, Opt_v3,
74 	Opt_udp, Opt_tcp, Opt_rdma,
75 	Opt_acl, Opt_noacl,
76 	Opt_rdirplus, Opt_nordirplus,
77 	Opt_sharecache, Opt_nosharecache,
78 	Opt_resvport, Opt_noresvport,
79 
80 	/* Mount options that take integer arguments */
81 	Opt_port,
82 	Opt_rsize, Opt_wsize, Opt_bsize,
83 	Opt_timeo, Opt_retrans,
84 	Opt_acregmin, Opt_acregmax,
85 	Opt_acdirmin, Opt_acdirmax,
86 	Opt_actimeo,
87 	Opt_namelen,
88 	Opt_mountport,
89 	Opt_mountvers,
90 	Opt_nfsvers,
91 
92 	/* Mount options that take string arguments */
93 	Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
94 	Opt_addr, Opt_mountaddr, Opt_clientaddr,
95 	Opt_lookupcache,
96 
97 	/* Special mount options */
98 	Opt_userspace, Opt_deprecated, Opt_sloppy,
99 
100 	Opt_err
101 };
102 
103 static const match_table_t nfs_mount_option_tokens = {
104 	{ Opt_userspace, "bg" },
105 	{ Opt_userspace, "fg" },
106 	{ Opt_userspace, "retry=%s" },
107 
108 	{ Opt_sloppy, "sloppy" },
109 
110 	{ Opt_soft, "soft" },
111 	{ Opt_hard, "hard" },
112 	{ Opt_deprecated, "intr" },
113 	{ Opt_deprecated, "nointr" },
114 	{ Opt_posix, "posix" },
115 	{ Opt_noposix, "noposix" },
116 	{ Opt_cto, "cto" },
117 	{ Opt_nocto, "nocto" },
118 	{ Opt_ac, "ac" },
119 	{ Opt_noac, "noac" },
120 	{ Opt_lock, "lock" },
121 	{ Opt_nolock, "nolock" },
122 	{ Opt_v2, "v2" },
123 	{ Opt_v3, "v3" },
124 	{ Opt_udp, "udp" },
125 	{ Opt_tcp, "tcp" },
126 	{ Opt_rdma, "rdma" },
127 	{ Opt_acl, "acl" },
128 	{ Opt_noacl, "noacl" },
129 	{ Opt_rdirplus, "rdirplus" },
130 	{ Opt_nordirplus, "nordirplus" },
131 	{ Opt_sharecache, "sharecache" },
132 	{ Opt_nosharecache, "nosharecache" },
133 	{ Opt_resvport, "resvport" },
134 	{ Opt_noresvport, "noresvport" },
135 
136 	{ Opt_port, "port=%u" },
137 	{ Opt_rsize, "rsize=%u" },
138 	{ Opt_wsize, "wsize=%u" },
139 	{ Opt_bsize, "bsize=%u" },
140 	{ Opt_timeo, "timeo=%u" },
141 	{ Opt_retrans, "retrans=%u" },
142 	{ Opt_acregmin, "acregmin=%u" },
143 	{ Opt_acregmax, "acregmax=%u" },
144 	{ Opt_acdirmin, "acdirmin=%u" },
145 	{ Opt_acdirmax, "acdirmax=%u" },
146 	{ Opt_actimeo, "actimeo=%u" },
147 	{ Opt_namelen, "namlen=%u" },
148 	{ Opt_mountport, "mountport=%u" },
149 	{ Opt_mountvers, "mountvers=%u" },
150 	{ Opt_nfsvers, "nfsvers=%u" },
151 	{ Opt_nfsvers, "vers=%u" },
152 
153 	{ Opt_sec, "sec=%s" },
154 	{ Opt_proto, "proto=%s" },
155 	{ Opt_mountproto, "mountproto=%s" },
156 	{ Opt_addr, "addr=%s" },
157 	{ Opt_clientaddr, "clientaddr=%s" },
158 	{ Opt_mounthost, "mounthost=%s" },
159 	{ Opt_mountaddr, "mountaddr=%s" },
160 
161 	{ Opt_lookupcache, "lookupcache=%s" },
162 
163 	{ Opt_err, NULL }
164 };
165 
166 enum {
167 	Opt_xprt_udp, Opt_xprt_tcp, Opt_xprt_rdma,
168 
169 	Opt_xprt_err
170 };
171 
172 static const match_table_t nfs_xprt_protocol_tokens = {
173 	{ Opt_xprt_udp, "udp" },
174 	{ Opt_xprt_tcp, "tcp" },
175 	{ Opt_xprt_rdma, "rdma" },
176 
177 	{ Opt_xprt_err, NULL }
178 };
179 
180 enum {
181 	Opt_sec_none, Opt_sec_sys,
182 	Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
183 	Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
184 	Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
185 
186 	Opt_sec_err
187 };
188 
189 static const match_table_t nfs_secflavor_tokens = {
190 	{ Opt_sec_none, "none" },
191 	{ Opt_sec_none, "null" },
192 	{ Opt_sec_sys, "sys" },
193 
194 	{ Opt_sec_krb5, "krb5" },
195 	{ Opt_sec_krb5i, "krb5i" },
196 	{ Opt_sec_krb5p, "krb5p" },
197 
198 	{ Opt_sec_lkey, "lkey" },
199 	{ Opt_sec_lkeyi, "lkeyi" },
200 	{ Opt_sec_lkeyp, "lkeyp" },
201 
202 	{ Opt_sec_spkm, "spkm3" },
203 	{ Opt_sec_spkmi, "spkm3i" },
204 	{ Opt_sec_spkmp, "spkm3p" },
205 
206 	{ Opt_sec_err, NULL }
207 };
208 
209 enum {
210 	Opt_lookupcache_all, Opt_lookupcache_positive,
211 	Opt_lookupcache_none,
212 
213 	Opt_lookupcache_err
214 };
215 
216 static match_table_t nfs_lookupcache_tokens = {
217 	{ Opt_lookupcache_all, "all" },
218 	{ Opt_lookupcache_positive, "pos" },
219 	{ Opt_lookupcache_positive, "positive" },
220 	{ Opt_lookupcache_none, "none" },
221 
222 	{ Opt_lookupcache_err, NULL }
223 };
224 
225 
226 static void nfs_umount_begin(struct super_block *);
227 static int  nfs_statfs(struct dentry *, struct kstatfs *);
228 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
229 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
230 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
231 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
232 		int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
233 static void nfs_kill_super(struct super_block *);
234 static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
235 
236 static struct file_system_type nfs_fs_type = {
237 	.owner		= THIS_MODULE,
238 	.name		= "nfs",
239 	.get_sb		= nfs_get_sb,
240 	.kill_sb	= nfs_kill_super,
241 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
242 };
243 
244 struct file_system_type nfs_xdev_fs_type = {
245 	.owner		= THIS_MODULE,
246 	.name		= "nfs",
247 	.get_sb		= nfs_xdev_get_sb,
248 	.kill_sb	= nfs_kill_super,
249 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
250 };
251 
252 static const struct super_operations nfs_sops = {
253 	.alloc_inode	= nfs_alloc_inode,
254 	.destroy_inode	= nfs_destroy_inode,
255 	.write_inode	= nfs_write_inode,
256 	.statfs		= nfs_statfs,
257 	.clear_inode	= nfs_clear_inode,
258 	.umount_begin	= nfs_umount_begin,
259 	.show_options	= nfs_show_options,
260 	.show_stats	= nfs_show_stats,
261 	.remount_fs	= nfs_remount,
262 };
263 
264 #ifdef CONFIG_NFS_V4
265 static int nfs4_get_sb(struct file_system_type *fs_type,
266 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
267 static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
268 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
269 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
270 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
271 static void nfs4_kill_super(struct super_block *sb);
272 
273 static struct file_system_type nfs4_fs_type = {
274 	.owner		= THIS_MODULE,
275 	.name		= "nfs4",
276 	.get_sb		= nfs4_get_sb,
277 	.kill_sb	= nfs4_kill_super,
278 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
279 };
280 
281 struct file_system_type nfs4_xdev_fs_type = {
282 	.owner		= THIS_MODULE,
283 	.name		= "nfs4",
284 	.get_sb		= nfs4_xdev_get_sb,
285 	.kill_sb	= nfs4_kill_super,
286 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
287 };
288 
289 struct file_system_type nfs4_referral_fs_type = {
290 	.owner		= THIS_MODULE,
291 	.name		= "nfs4",
292 	.get_sb		= nfs4_referral_get_sb,
293 	.kill_sb	= nfs4_kill_super,
294 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
295 };
296 
297 static const struct super_operations nfs4_sops = {
298 	.alloc_inode	= nfs_alloc_inode,
299 	.destroy_inode	= nfs_destroy_inode,
300 	.write_inode	= nfs_write_inode,
301 	.statfs		= nfs_statfs,
302 	.clear_inode	= nfs4_clear_inode,
303 	.umount_begin	= nfs_umount_begin,
304 	.show_options	= nfs_show_options,
305 	.show_stats	= nfs_show_stats,
306 	.remount_fs	= nfs_remount,
307 };
308 #endif
309 
310 static struct shrinker acl_shrinker = {
311 	.shrink		= nfs_access_cache_shrinker,
312 	.seeks		= DEFAULT_SEEKS,
313 };
314 
315 /*
316  * Register the NFS filesystems
317  */
318 int __init register_nfs_fs(void)
319 {
320 	int ret;
321 
322         ret = register_filesystem(&nfs_fs_type);
323 	if (ret < 0)
324 		goto error_0;
325 
326 	ret = nfs_register_sysctl();
327 	if (ret < 0)
328 		goto error_1;
329 #ifdef CONFIG_NFS_V4
330 	ret = register_filesystem(&nfs4_fs_type);
331 	if (ret < 0)
332 		goto error_2;
333 #endif
334 	register_shrinker(&acl_shrinker);
335 	return 0;
336 
337 #ifdef CONFIG_NFS_V4
338 error_2:
339 	nfs_unregister_sysctl();
340 #endif
341 error_1:
342 	unregister_filesystem(&nfs_fs_type);
343 error_0:
344 	return ret;
345 }
346 
347 /*
348  * Unregister the NFS filesystems
349  */
350 void __exit unregister_nfs_fs(void)
351 {
352 	unregister_shrinker(&acl_shrinker);
353 #ifdef CONFIG_NFS_V4
354 	unregister_filesystem(&nfs4_fs_type);
355 #endif
356 	nfs_unregister_sysctl();
357 	unregister_filesystem(&nfs_fs_type);
358 }
359 
360 void nfs_sb_active(struct super_block *sb)
361 {
362 	struct nfs_server *server = NFS_SB(sb);
363 
364 	if (atomic_inc_return(&server->active) == 1)
365 		atomic_inc(&sb->s_active);
366 }
367 
368 void nfs_sb_deactive(struct super_block *sb)
369 {
370 	struct nfs_server *server = NFS_SB(sb);
371 
372 	if (atomic_dec_and_test(&server->active))
373 		deactivate_super(sb);
374 }
375 
376 /*
377  * Deliver file system statistics to userspace
378  */
379 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
380 {
381 	struct nfs_server *server = NFS_SB(dentry->d_sb);
382 	unsigned char blockbits;
383 	unsigned long blockres;
384 	struct nfs_fh *fh = NFS_FH(dentry->d_inode);
385 	struct nfs_fattr fattr;
386 	struct nfs_fsstat res = {
387 			.fattr = &fattr,
388 	};
389 	int error;
390 
391 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
392 	if (error < 0)
393 		goto out_err;
394 	buf->f_type = NFS_SUPER_MAGIC;
395 
396 	/*
397 	 * Current versions of glibc do not correctly handle the
398 	 * case where f_frsize != f_bsize.  Eventually we want to
399 	 * report the value of wtmult in this field.
400 	 */
401 	buf->f_frsize = dentry->d_sb->s_blocksize;
402 
403 	/*
404 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
405 	 * are reported in units of f_frsize.  Linux hasn't had
406 	 * an f_frsize field in its statfs struct until recently,
407 	 * thus historically Linux's sys_statfs reports these
408 	 * fields in units of f_bsize.
409 	 */
410 	buf->f_bsize = dentry->d_sb->s_blocksize;
411 	blockbits = dentry->d_sb->s_blocksize_bits;
412 	blockres = (1 << blockbits) - 1;
413 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
414 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
415 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
416 
417 	buf->f_files = res.tfiles;
418 	buf->f_ffree = res.afiles;
419 
420 	buf->f_namelen = server->namelen;
421 
422 	return 0;
423 
424  out_err:
425 	dprintk("%s: statfs error = %d\n", __func__, -error);
426 	return error;
427 }
428 
429 /*
430  * Map the security flavour number to a name
431  */
432 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
433 {
434 	static const struct {
435 		rpc_authflavor_t flavour;
436 		const char *str;
437 	} sec_flavours[] = {
438 		{ RPC_AUTH_NULL, "null" },
439 		{ RPC_AUTH_UNIX, "sys" },
440 		{ RPC_AUTH_GSS_KRB5, "krb5" },
441 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
442 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
443 		{ RPC_AUTH_GSS_LKEY, "lkey" },
444 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
445 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
446 		{ RPC_AUTH_GSS_SPKM, "spkm" },
447 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
448 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
449 		{ UINT_MAX, "unknown" }
450 	};
451 	int i;
452 
453 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
454 		if (sec_flavours[i].flavour == flavour)
455 			break;
456 	}
457 	return sec_flavours[i].str;
458 }
459 
460 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
461 				    int showdefaults)
462 {
463 	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
464 
465 	switch (sap->sa_family) {
466 	case AF_INET: {
467 		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
468 		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
469 		break;
470 	}
471 	case AF_INET6: {
472 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
473 		seq_printf(m, ",mountaddr=%pI6", &sin6->sin6_addr);
474 		break;
475 	}
476 	default:
477 		if (showdefaults)
478 			seq_printf(m, ",mountaddr=unspecified");
479 	}
480 
481 	if (nfss->mountd_version || showdefaults)
482 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
483 	if (nfss->mountd_port || showdefaults)
484 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
485 
486 	switch (nfss->mountd_protocol) {
487 	case IPPROTO_UDP:
488 		seq_printf(m, ",mountproto=udp");
489 		break;
490 	case IPPROTO_TCP:
491 		seq_printf(m, ",mountproto=tcp");
492 		break;
493 	default:
494 		if (showdefaults)
495 			seq_printf(m, ",mountproto=auto");
496 	}
497 }
498 
499 /*
500  * Describe the mount options in force on this server representation
501  */
502 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
503 				   int showdefaults)
504 {
505 	static const struct proc_nfs_info {
506 		int flag;
507 		const char *str;
508 		const char *nostr;
509 	} nfs_info[] = {
510 		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
511 		{ NFS_MOUNT_INTR, ",intr", ",nointr" },
512 		{ NFS_MOUNT_POSIX, ",posix", "" },
513 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
514 		{ NFS_MOUNT_NOAC, ",noac", "" },
515 		{ NFS_MOUNT_NONLM, ",nolock", "" },
516 		{ NFS_MOUNT_NOACL, ",noacl", "" },
517 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
518 		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
519 		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
520 		{ 0, NULL, NULL }
521 	};
522 	const struct proc_nfs_info *nfs_infop;
523 	struct nfs_client *clp = nfss->nfs_client;
524 	u32 version = clp->rpc_ops->version;
525 
526 	seq_printf(m, ",vers=%u", version);
527 	seq_printf(m, ",rsize=%u", nfss->rsize);
528 	seq_printf(m, ",wsize=%u", nfss->wsize);
529 	if (nfss->bsize != 0)
530 		seq_printf(m, ",bsize=%u", nfss->bsize);
531 	seq_printf(m, ",namlen=%u", nfss->namelen);
532 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
533 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
534 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
535 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
536 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
537 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
538 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
539 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
540 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
541 		if (nfss->flags & nfs_infop->flag)
542 			seq_puts(m, nfs_infop->str);
543 		else
544 			seq_puts(m, nfs_infop->nostr);
545 	}
546 	seq_printf(m, ",proto=%s",
547 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
548 	if (version == 4) {
549 		if (nfss->port != NFS_PORT)
550 			seq_printf(m, ",port=%u", nfss->port);
551 	} else
552 		if (nfss->port)
553 			seq_printf(m, ",port=%u", nfss->port);
554 
555 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
556 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
557 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
558 
559 	if (version != 4)
560 		nfs_show_mountd_options(m, nfss, showdefaults);
561 
562 #ifdef CONFIG_NFS_V4
563 	if (clp->rpc_ops->version == 4)
564 		seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
565 #endif
566 }
567 
568 /*
569  * Describe the mount options on this VFS mountpoint
570  */
571 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
572 {
573 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
574 
575 	nfs_show_mount_options(m, nfss, 0);
576 
577 	seq_printf(m, ",addr=%s",
578 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
579 							RPC_DISPLAY_ADDR));
580 
581 	return 0;
582 }
583 
584 /*
585  * Present statistical information for this VFS mountpoint
586  */
587 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
588 {
589 	int i, cpu;
590 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
591 	struct rpc_auth *auth = nfss->client->cl_auth;
592 	struct nfs_iostats totals = { };
593 
594 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
595 
596 	/*
597 	 * Display all mount option settings
598 	 */
599 	seq_printf(m, "\n\topts:\t");
600 	seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
601 	seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
602 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
603 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
604 	nfs_show_mount_options(m, nfss, 1);
605 
606 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
607 
608 	seq_printf(m, "\n\tcaps:\t");
609 	seq_printf(m, "caps=0x%x", nfss->caps);
610 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
611 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
612 	seq_printf(m, ",bsize=%u", nfss->bsize);
613 	seq_printf(m, ",namlen=%u", nfss->namelen);
614 
615 #ifdef CONFIG_NFS_V4
616 	if (nfss->nfs_client->rpc_ops->version == 4) {
617 		seq_printf(m, "\n\tnfsv4:\t");
618 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
619 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
620 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
621 	}
622 #endif
623 
624 	/*
625 	 * Display security flavor in effect for this mount
626 	 */
627 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
628 	if (auth->au_flavor)
629 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
630 
631 	/*
632 	 * Display superblock I/O counters
633 	 */
634 	for_each_possible_cpu(cpu) {
635 		struct nfs_iostats *stats;
636 
637 		preempt_disable();
638 		stats = per_cpu_ptr(nfss->io_stats, cpu);
639 
640 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
641 			totals.events[i] += stats->events[i];
642 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
643 			totals.bytes[i] += stats->bytes[i];
644 
645 		preempt_enable();
646 	}
647 
648 	seq_printf(m, "\n\tevents:\t");
649 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
650 		seq_printf(m, "%lu ", totals.events[i]);
651 	seq_printf(m, "\n\tbytes:\t");
652 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
653 		seq_printf(m, "%Lu ", totals.bytes[i]);
654 	seq_printf(m, "\n");
655 
656 	rpc_print_iostats(m, nfss->client);
657 
658 	return 0;
659 }
660 
661 /*
662  * Begin unmount by attempting to remove all automounted mountpoints we added
663  * in response to xdev traversals and referrals
664  */
665 static void nfs_umount_begin(struct super_block *sb)
666 {
667 	struct nfs_server *server = NFS_SB(sb);
668 	struct rpc_clnt *rpc;
669 
670 	/* -EIO all pending I/O */
671 	rpc = server->client_acl;
672 	if (!IS_ERR(rpc))
673 		rpc_killall_tasks(rpc);
674 	rpc = server->client;
675 	if (!IS_ERR(rpc))
676 		rpc_killall_tasks(rpc);
677 }
678 
679 /*
680  * Sanity-check a server address provided by the mount command.
681  *
682  * Address family must be initialized, and address must not be
683  * the ANY address for that family.
684  */
685 static int nfs_verify_server_address(struct sockaddr *addr)
686 {
687 	switch (addr->sa_family) {
688 	case AF_INET: {
689 		struct sockaddr_in *sa = (struct sockaddr_in *)addr;
690 		return sa->sin_addr.s_addr != htonl(INADDR_ANY);
691 	}
692 	case AF_INET6: {
693 		struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
694 		return !ipv6_addr_any(sa);
695 	}
696 	}
697 
698 	return 0;
699 }
700 
701 static void nfs_parse_ipv4_address(char *string, size_t str_len,
702 				   struct sockaddr *sap, size_t *addr_len)
703 {
704 	struct sockaddr_in *sin = (struct sockaddr_in *)sap;
705 	u8 *addr = (u8 *)&sin->sin_addr.s_addr;
706 
707 	if (str_len <= INET_ADDRSTRLEN) {
708 		dfprintk(MOUNT, "NFS: parsing IPv4 address %*s\n",
709 				(int)str_len, string);
710 
711 		sin->sin_family = AF_INET;
712 		*addr_len = sizeof(*sin);
713 		if (in4_pton(string, str_len, addr, '\0', NULL))
714 			return;
715 	}
716 
717 	sap->sa_family = AF_UNSPEC;
718 	*addr_len = 0;
719 }
720 
721 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
722 static int nfs_parse_ipv6_scope_id(const char *string, const size_t str_len,
723 				   const char *delim,
724 				   struct sockaddr_in6 *sin6)
725 {
726 	char *p;
727 	size_t len;
728 
729 	if ((string + str_len) == delim)
730 		return 1;
731 
732 	if (*delim != IPV6_SCOPE_DELIMITER)
733 		return 0;
734 
735 	if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
736 		return 0;
737 
738 	len = (string + str_len) - delim - 1;
739 	p = kstrndup(delim + 1, len, GFP_KERNEL);
740 	if (p) {
741 		unsigned long scope_id = 0;
742 		struct net_device *dev;
743 
744 		dev = dev_get_by_name(&init_net, p);
745 		if (dev != NULL) {
746 			scope_id = dev->ifindex;
747 			dev_put(dev);
748 		} else {
749 			if (strict_strtoul(p, 10, &scope_id) == 0) {
750 				kfree(p);
751 				return 0;
752 			}
753 		}
754 
755 		kfree(p);
756 
757 		sin6->sin6_scope_id = scope_id;
758 		dfprintk(MOUNT, "NFS: IPv6 scope ID = %lu\n", scope_id);
759 		return 1;
760 	}
761 
762 	return 0;
763 }
764 
765 static void nfs_parse_ipv6_address(char *string, size_t str_len,
766 				   struct sockaddr *sap, size_t *addr_len)
767 {
768 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
769 	u8 *addr = (u8 *)&sin6->sin6_addr.in6_u;
770 	const char *delim;
771 
772 	if (str_len <= INET6_ADDRSTRLEN) {
773 		dfprintk(MOUNT, "NFS: parsing IPv6 address %*s\n",
774 				(int)str_len, string);
775 
776 		sin6->sin6_family = AF_INET6;
777 		*addr_len = sizeof(*sin6);
778 		if (in6_pton(string, str_len, addr,
779 					IPV6_SCOPE_DELIMITER, &delim) != 0) {
780 			if (nfs_parse_ipv6_scope_id(string, str_len,
781 							delim, sin6) != 0)
782 				return;
783 		}
784 	}
785 
786 	sap->sa_family = AF_UNSPEC;
787 	*addr_len = 0;
788 }
789 #else
790 static void nfs_parse_ipv6_address(char *string, size_t str_len,
791 				   struct sockaddr *sap, size_t *addr_len)
792 {
793 	sap->sa_family = AF_UNSPEC;
794 	*addr_len = 0;
795 }
796 #endif
797 
798 /*
799  * Construct a sockaddr based on the contents of a string that contains
800  * an IP address in presentation format.
801  *
802  * If there is a problem constructing the new sockaddr, set the address
803  * family to AF_UNSPEC.
804  */
805 void nfs_parse_ip_address(char *string, size_t str_len,
806 				 struct sockaddr *sap, size_t *addr_len)
807 {
808 	unsigned int i, colons;
809 
810 	colons = 0;
811 	for (i = 0; i < str_len; i++)
812 		if (string[i] == ':')
813 			colons++;
814 
815 	if (colons >= 2)
816 		nfs_parse_ipv6_address(string, str_len, sap, addr_len);
817 	else
818 		nfs_parse_ipv4_address(string, str_len, sap, addr_len);
819 }
820 
821 /*
822  * Sanity check the NFS transport protocol.
823  *
824  */
825 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
826 {
827 	switch (mnt->nfs_server.protocol) {
828 	case XPRT_TRANSPORT_UDP:
829 	case XPRT_TRANSPORT_TCP:
830 	case XPRT_TRANSPORT_RDMA:
831 		break;
832 	default:
833 		mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
834 	}
835 }
836 
837 /*
838  * For text based NFSv2/v3 mounts, the mount protocol transport default
839  * settings should depend upon the specified NFS transport.
840  */
841 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
842 {
843 	nfs_validate_transport_protocol(mnt);
844 
845 	if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
846 	    mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
847 			return;
848 	switch (mnt->nfs_server.protocol) {
849 	case XPRT_TRANSPORT_UDP:
850 		mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
851 		break;
852 	case XPRT_TRANSPORT_TCP:
853 	case XPRT_TRANSPORT_RDMA:
854 		mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
855 	}
856 }
857 
858 /*
859  * Parse the value of the 'sec=' option.
860  *
861  * The flavor_len setting is for v4 mounts.
862  */
863 static int nfs_parse_security_flavors(char *value,
864 				      struct nfs_parsed_mount_data *mnt)
865 {
866 	substring_t args[MAX_OPT_ARGS];
867 
868 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
869 
870 	switch (match_token(value, nfs_secflavor_tokens, args)) {
871 	case Opt_sec_none:
872 		mnt->auth_flavor_len = 0;
873 		mnt->auth_flavors[0] = RPC_AUTH_NULL;
874 		break;
875 	case Opt_sec_sys:
876 		mnt->auth_flavor_len = 0;
877 		mnt->auth_flavors[0] = RPC_AUTH_UNIX;
878 		break;
879 	case Opt_sec_krb5:
880 		mnt->auth_flavor_len = 1;
881 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
882 		break;
883 	case Opt_sec_krb5i:
884 		mnt->auth_flavor_len = 1;
885 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
886 		break;
887 	case Opt_sec_krb5p:
888 		mnt->auth_flavor_len = 1;
889 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
890 		break;
891 	case Opt_sec_lkey:
892 		mnt->auth_flavor_len = 1;
893 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
894 		break;
895 	case Opt_sec_lkeyi:
896 		mnt->auth_flavor_len = 1;
897 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
898 		break;
899 	case Opt_sec_lkeyp:
900 		mnt->auth_flavor_len = 1;
901 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
902 		break;
903 	case Opt_sec_spkm:
904 		mnt->auth_flavor_len = 1;
905 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
906 		break;
907 	case Opt_sec_spkmi:
908 		mnt->auth_flavor_len = 1;
909 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
910 		break;
911 	case Opt_sec_spkmp:
912 		mnt->auth_flavor_len = 1;
913 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
914 		break;
915 	default:
916 		return 0;
917 	}
918 
919 	return 1;
920 }
921 
922 static void nfs_parse_invalid_value(const char *option)
923 {
924 	dfprintk(MOUNT, "NFS:   bad value specified for %s option\n", option);
925 }
926 
927 /*
928  * Error-check and convert a string of mount options from user space into
929  * a data structure.  The whole mount string is processed; bad options are
930  * skipped as they are encountered.  If there were no errors, return 1;
931  * otherwise return 0 (zero).
932  */
933 static int nfs_parse_mount_options(char *raw,
934 				   struct nfs_parsed_mount_data *mnt)
935 {
936 	char *p, *string, *secdata;
937 	int rc, sloppy = 0, errors = 0;
938 
939 	if (!raw) {
940 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
941 		return 1;
942 	}
943 	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
944 
945 	secdata = alloc_secdata();
946 	if (!secdata)
947 		goto out_nomem;
948 
949 	rc = security_sb_copy_data(raw, secdata);
950 	if (rc)
951 		goto out_security_failure;
952 
953 	rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
954 	if (rc)
955 		goto out_security_failure;
956 
957 	free_secdata(secdata);
958 
959 	while ((p = strsep(&raw, ",")) != NULL) {
960 		substring_t args[MAX_OPT_ARGS];
961 		int option, token;
962 
963 		if (!*p)
964 			continue;
965 
966 		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
967 
968 		token = match_token(p, nfs_mount_option_tokens, args);
969 		switch (token) {
970 
971 		/*
972 		 * boolean options:  foo/nofoo
973 		 */
974 		case Opt_soft:
975 			mnt->flags |= NFS_MOUNT_SOFT;
976 			break;
977 		case Opt_hard:
978 			mnt->flags &= ~NFS_MOUNT_SOFT;
979 			break;
980 		case Opt_posix:
981 			mnt->flags |= NFS_MOUNT_POSIX;
982 			break;
983 		case Opt_noposix:
984 			mnt->flags &= ~NFS_MOUNT_POSIX;
985 			break;
986 		case Opt_cto:
987 			mnt->flags &= ~NFS_MOUNT_NOCTO;
988 			break;
989 		case Opt_nocto:
990 			mnt->flags |= NFS_MOUNT_NOCTO;
991 			break;
992 		case Opt_ac:
993 			mnt->flags &= ~NFS_MOUNT_NOAC;
994 			break;
995 		case Opt_noac:
996 			mnt->flags |= NFS_MOUNT_NOAC;
997 			break;
998 		case Opt_lock:
999 			mnt->flags &= ~NFS_MOUNT_NONLM;
1000 			break;
1001 		case Opt_nolock:
1002 			mnt->flags |= NFS_MOUNT_NONLM;
1003 			break;
1004 		case Opt_v2:
1005 			mnt->flags &= ~NFS_MOUNT_VER3;
1006 			break;
1007 		case Opt_v3:
1008 			mnt->flags |= NFS_MOUNT_VER3;
1009 			break;
1010 		case Opt_udp:
1011 			mnt->flags &= ~NFS_MOUNT_TCP;
1012 			mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1013 			break;
1014 		case Opt_tcp:
1015 			mnt->flags |= NFS_MOUNT_TCP;
1016 			mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1017 			break;
1018 		case Opt_rdma:
1019 			mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1020 			mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1021 			xprt_load_transport(p);
1022 			break;
1023 		case Opt_acl:
1024 			mnt->flags &= ~NFS_MOUNT_NOACL;
1025 			break;
1026 		case Opt_noacl:
1027 			mnt->flags |= NFS_MOUNT_NOACL;
1028 			break;
1029 		case Opt_rdirplus:
1030 			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1031 			break;
1032 		case Opt_nordirplus:
1033 			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1034 			break;
1035 		case Opt_sharecache:
1036 			mnt->flags &= ~NFS_MOUNT_UNSHARED;
1037 			break;
1038 		case Opt_nosharecache:
1039 			mnt->flags |= NFS_MOUNT_UNSHARED;
1040 			break;
1041 		case Opt_resvport:
1042 			mnt->flags &= ~NFS_MOUNT_NORESVPORT;
1043 			break;
1044 		case Opt_noresvport:
1045 			mnt->flags |= NFS_MOUNT_NORESVPORT;
1046 			break;
1047 
1048 		/*
1049 		 * options that take numeric values
1050 		 */
1051 		case Opt_port:
1052 			if (match_int(args, &option) ||
1053 			    option < 0 || option > USHORT_MAX) {
1054 				errors++;
1055 				nfs_parse_invalid_value("port");
1056 			} else
1057 				mnt->nfs_server.port = option;
1058 			break;
1059 		case Opt_rsize:
1060 			if (match_int(args, &option) || option < 0) {
1061 				errors++;
1062 				nfs_parse_invalid_value("rsize");
1063 			} else
1064 				mnt->rsize = option;
1065 			break;
1066 		case Opt_wsize:
1067 			if (match_int(args, &option) || option < 0) {
1068 				errors++;
1069 				nfs_parse_invalid_value("wsize");
1070 			} else
1071 				mnt->wsize = option;
1072 			break;
1073 		case Opt_bsize:
1074 			if (match_int(args, &option) || option < 0) {
1075 				errors++;
1076 				nfs_parse_invalid_value("bsize");
1077 			} else
1078 				mnt->bsize = option;
1079 			break;
1080 		case Opt_timeo:
1081 			if (match_int(args, &option) || option <= 0) {
1082 				errors++;
1083 				nfs_parse_invalid_value("timeo");
1084 			} else
1085 				mnt->timeo = option;
1086 			break;
1087 		case Opt_retrans:
1088 			if (match_int(args, &option) || option <= 0) {
1089 				errors++;
1090 				nfs_parse_invalid_value("retrans");
1091 			} else
1092 				mnt->retrans = option;
1093 			break;
1094 		case Opt_acregmin:
1095 			if (match_int(args, &option) || option < 0) {
1096 				errors++;
1097 				nfs_parse_invalid_value("acregmin");
1098 			} else
1099 				mnt->acregmin = option;
1100 			break;
1101 		case Opt_acregmax:
1102 			if (match_int(args, &option) || option < 0) {
1103 				errors++;
1104 				nfs_parse_invalid_value("acregmax");
1105 			} else
1106 				mnt->acregmax = option;
1107 			break;
1108 		case Opt_acdirmin:
1109 			if (match_int(args, &option) || option < 0) {
1110 				errors++;
1111 				nfs_parse_invalid_value("acdirmin");
1112 			} else
1113 				mnt->acdirmin = option;
1114 			break;
1115 		case Opt_acdirmax:
1116 			if (match_int(args, &option) || option < 0) {
1117 				errors++;
1118 				nfs_parse_invalid_value("acdirmax");
1119 			} else
1120 				mnt->acdirmax = option;
1121 			break;
1122 		case Opt_actimeo:
1123 			if (match_int(args, &option) || option < 0) {
1124 				errors++;
1125 				nfs_parse_invalid_value("actimeo");
1126 			} else
1127 				mnt->acregmin = mnt->acregmax =
1128 				mnt->acdirmin = mnt->acdirmax = option;
1129 			break;
1130 		case Opt_namelen:
1131 			if (match_int(args, &option) || option < 0) {
1132 				errors++;
1133 				nfs_parse_invalid_value("namlen");
1134 			} else
1135 				mnt->namlen = option;
1136 			break;
1137 		case Opt_mountport:
1138 			if (match_int(args, &option) ||
1139 			    option < 0 || option > USHORT_MAX) {
1140 				errors++;
1141 				nfs_parse_invalid_value("mountport");
1142 			} else
1143 				mnt->mount_server.port = option;
1144 			break;
1145 		case Opt_mountvers:
1146 			if (match_int(args, &option) ||
1147 			    option < NFS_MNT_VERSION ||
1148 			    option > NFS_MNT3_VERSION) {
1149 				errors++;
1150 				nfs_parse_invalid_value("mountvers");
1151 			} else
1152 				mnt->mount_server.version = option;
1153 			break;
1154 		case Opt_nfsvers:
1155 			if (match_int(args, &option)) {
1156 				errors++;
1157 				nfs_parse_invalid_value("nfsvers");
1158 				break;
1159 			}
1160 			switch (option) {
1161 			case NFS2_VERSION:
1162 				mnt->flags &= ~NFS_MOUNT_VER3;
1163 				break;
1164 			case NFS3_VERSION:
1165 				mnt->flags |= NFS_MOUNT_VER3;
1166 				break;
1167 			default:
1168 				errors++;
1169 				nfs_parse_invalid_value("nfsvers");
1170 			}
1171 			break;
1172 
1173 		/*
1174 		 * options that take text values
1175 		 */
1176 		case Opt_sec:
1177 			string = match_strdup(args);
1178 			if (string == NULL)
1179 				goto out_nomem;
1180 			rc = nfs_parse_security_flavors(string, mnt);
1181 			kfree(string);
1182 			if (!rc) {
1183 				errors++;
1184 				dfprintk(MOUNT, "NFS:   unrecognized "
1185 						"security flavor\n");
1186 			}
1187 			break;
1188 		case Opt_proto:
1189 			string = match_strdup(args);
1190 			if (string == NULL)
1191 				goto out_nomem;
1192 			token = match_token(string,
1193 					    nfs_xprt_protocol_tokens, args);
1194 			kfree(string);
1195 
1196 			switch (token) {
1197 			case Opt_xprt_udp:
1198 				mnt->flags &= ~NFS_MOUNT_TCP;
1199 				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1200 				break;
1201 			case Opt_xprt_tcp:
1202 				mnt->flags |= NFS_MOUNT_TCP;
1203 				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1204 				break;
1205 			case Opt_xprt_rdma:
1206 				/* vector side protocols to TCP */
1207 				mnt->flags |= NFS_MOUNT_TCP;
1208 				mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1209 				xprt_load_transport(string);
1210 				break;
1211 			default:
1212 				errors++;
1213 				dfprintk(MOUNT, "NFS:   unrecognized "
1214 						"transport protocol\n");
1215 			}
1216 			kfree(string);
1217 			break;
1218 		case Opt_mountproto:
1219 			string = match_strdup(args);
1220 			if (string == NULL)
1221 				goto out_nomem;
1222 			token = match_token(string,
1223 					    nfs_xprt_protocol_tokens, args);
1224 
1225 			switch (token) {
1226 			case Opt_xprt_udp:
1227 				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1228 				break;
1229 			case Opt_xprt_tcp:
1230 				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1231 				break;
1232 			case Opt_xprt_rdma: /* not used for side protocols */
1233 			default:
1234 				errors++;
1235 				dfprintk(MOUNT, "NFS:   unrecognized "
1236 						"transport protocol\n");
1237 			}
1238 			break;
1239 		case Opt_addr:
1240 			string = match_strdup(args);
1241 			if (string == NULL)
1242 				goto out_nomem;
1243 			nfs_parse_ip_address(string, strlen(string),
1244 					     (struct sockaddr *)
1245 						&mnt->nfs_server.address,
1246 					     &mnt->nfs_server.addrlen);
1247 			kfree(string);
1248 			break;
1249 		case Opt_clientaddr:
1250 			string = match_strdup(args);
1251 			if (string == NULL)
1252 				goto out_nomem;
1253 			kfree(mnt->client_address);
1254 			mnt->client_address = string;
1255 			break;
1256 		case Opt_mounthost:
1257 			string = match_strdup(args);
1258 			if (string == NULL)
1259 				goto out_nomem;
1260 			kfree(mnt->mount_server.hostname);
1261 			mnt->mount_server.hostname = string;
1262 			break;
1263 		case Opt_mountaddr:
1264 			string = match_strdup(args);
1265 			if (string == NULL)
1266 				goto out_nomem;
1267 			nfs_parse_ip_address(string, strlen(string),
1268 					     (struct sockaddr *)
1269 						&mnt->mount_server.address,
1270 					     &mnt->mount_server.addrlen);
1271 			kfree(string);
1272 			break;
1273 		case Opt_lookupcache:
1274 			string = match_strdup(args);
1275 			if (string == NULL)
1276 				goto out_nomem;
1277 			token = match_token(string,
1278 					nfs_lookupcache_tokens, args);
1279 			kfree(string);
1280 			switch (token) {
1281 				case Opt_lookupcache_all:
1282 					mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1283 					break;
1284 				case Opt_lookupcache_positive:
1285 					mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1286 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1287 					break;
1288 				case Opt_lookupcache_none:
1289 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1290 					break;
1291 				default:
1292 					errors++;
1293 					dfprintk(MOUNT, "NFS:   invalid "
1294 							"lookupcache argument\n");
1295 			};
1296 			break;
1297 
1298 		/*
1299 		 * Special options
1300 		 */
1301 		case Opt_sloppy:
1302 			sloppy = 1;
1303 			dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1304 			break;
1305 		case Opt_userspace:
1306 		case Opt_deprecated:
1307 			dfprintk(MOUNT, "NFS:   ignoring mount option "
1308 					"'%s'\n", p);
1309 			break;
1310 
1311 		default:
1312 			errors++;
1313 			dfprintk(MOUNT, "NFS:   unrecognized mount option "
1314 					"'%s'\n", p);
1315 		}
1316 	}
1317 
1318 	if (errors > 0) {
1319 		dfprintk(MOUNT, "NFS: parsing encountered %d error%s\n",
1320 				errors, (errors == 1 ? "" : "s"));
1321 		if (!sloppy)
1322 			return 0;
1323 	}
1324 	return 1;
1325 
1326 out_nomem:
1327 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
1328 	return 0;
1329 out_security_failure:
1330 	free_secdata(secdata);
1331 	printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1332 	return 0;
1333 }
1334 
1335 /*
1336  * Use the remote server's MOUNT service to request the NFS file handle
1337  * corresponding to the provided path.
1338  */
1339 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1340 			 struct nfs_fh *root_fh)
1341 {
1342 	struct nfs_mount_request request = {
1343 		.sap		= (struct sockaddr *)
1344 						&args->mount_server.address,
1345 		.dirpath	= args->nfs_server.export_path,
1346 		.protocol	= args->mount_server.protocol,
1347 		.fh		= root_fh,
1348 		.noresvport	= args->flags & NFS_MOUNT_NORESVPORT,
1349 	};
1350 	int status;
1351 
1352 	if (args->mount_server.version == 0) {
1353 		if (args->flags & NFS_MOUNT_VER3)
1354 			args->mount_server.version = NFS_MNT3_VERSION;
1355 		else
1356 			args->mount_server.version = NFS_MNT_VERSION;
1357 	}
1358 	request.version = args->mount_server.version;
1359 
1360 	if (args->mount_server.hostname)
1361 		request.hostname = args->mount_server.hostname;
1362 	else
1363 		request.hostname = args->nfs_server.hostname;
1364 
1365 	/*
1366 	 * Construct the mount server's address.
1367 	 */
1368 	if (args->mount_server.address.ss_family == AF_UNSPEC) {
1369 		memcpy(request.sap, &args->nfs_server.address,
1370 		       args->nfs_server.addrlen);
1371 		args->mount_server.addrlen = args->nfs_server.addrlen;
1372 	}
1373 	request.salen = args->mount_server.addrlen;
1374 
1375 	/*
1376 	 * autobind will be used if mount_server.port == 0
1377 	 */
1378 	nfs_set_port(request.sap, args->mount_server.port);
1379 
1380 	/*
1381 	 * Now ask the mount server to map our export path
1382 	 * to a file handle.
1383 	 */
1384 	status = nfs_mount(&request);
1385 	if (status == 0)
1386 		return 0;
1387 
1388 	dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1389 			request.hostname, status);
1390 	return status;
1391 }
1392 
1393 static int nfs_parse_simple_hostname(const char *dev_name,
1394 				     char **hostname, size_t maxnamlen,
1395 				     char **export_path, size_t maxpathlen)
1396 {
1397 	size_t len;
1398 	char *colon, *comma;
1399 
1400 	colon = strchr(dev_name, ':');
1401 	if (colon == NULL)
1402 		goto out_bad_devname;
1403 
1404 	len = colon - dev_name;
1405 	if (len > maxnamlen)
1406 		goto out_hostname;
1407 
1408 	/* N.B. caller will free nfs_server.hostname in all cases */
1409 	*hostname = kstrndup(dev_name, len, GFP_KERNEL);
1410 	if (!*hostname)
1411 		goto out_nomem;
1412 
1413 	/* kill possible hostname list: not supported */
1414 	comma = strchr(*hostname, ',');
1415 	if (comma != NULL) {
1416 		if (comma == *hostname)
1417 			goto out_bad_devname;
1418 		*comma = '\0';
1419 	}
1420 
1421 	colon++;
1422 	len = strlen(colon);
1423 	if (len > maxpathlen)
1424 		goto out_path;
1425 	*export_path = kstrndup(colon, len, GFP_KERNEL);
1426 	if (!*export_path)
1427 		goto out_nomem;
1428 
1429 	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1430 	return 0;
1431 
1432 out_bad_devname:
1433 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1434 	return -EINVAL;
1435 
1436 out_nomem:
1437 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1438 	return -ENOMEM;
1439 
1440 out_hostname:
1441 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1442 	return -ENAMETOOLONG;
1443 
1444 out_path:
1445 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1446 	return -ENAMETOOLONG;
1447 }
1448 
1449 /*
1450  * Hostname has square brackets around it because it contains one or
1451  * more colons.  We look for the first closing square bracket, and a
1452  * colon must follow it.
1453  */
1454 static int nfs_parse_protected_hostname(const char *dev_name,
1455 					char **hostname, size_t maxnamlen,
1456 					char **export_path, size_t maxpathlen)
1457 {
1458 	size_t len;
1459 	char *start, *end;
1460 
1461 	start = (char *)(dev_name + 1);
1462 
1463 	end = strchr(start, ']');
1464 	if (end == NULL)
1465 		goto out_bad_devname;
1466 	if (*(end + 1) != ':')
1467 		goto out_bad_devname;
1468 
1469 	len = end - start;
1470 	if (len > maxnamlen)
1471 		goto out_hostname;
1472 
1473 	/* N.B. caller will free nfs_server.hostname in all cases */
1474 	*hostname = kstrndup(start, len, GFP_KERNEL);
1475 	if (*hostname == NULL)
1476 		goto out_nomem;
1477 
1478 	end += 2;
1479 	len = strlen(end);
1480 	if (len > maxpathlen)
1481 		goto out_path;
1482 	*export_path = kstrndup(end, len, GFP_KERNEL);
1483 	if (!*export_path)
1484 		goto out_nomem;
1485 
1486 	return 0;
1487 
1488 out_bad_devname:
1489 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1490 	return -EINVAL;
1491 
1492 out_nomem:
1493 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1494 	return -ENOMEM;
1495 
1496 out_hostname:
1497 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1498 	return -ENAMETOOLONG;
1499 
1500 out_path:
1501 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1502 	return -ENAMETOOLONG;
1503 }
1504 
1505 /*
1506  * Split "dev_name" into "hostname:export_path".
1507  *
1508  * The leftmost colon demarks the split between the server's hostname
1509  * and the export path.  If the hostname starts with a left square
1510  * bracket, then it may contain colons.
1511  *
1512  * Note: caller frees hostname and export path, even on error.
1513  */
1514 static int nfs_parse_devname(const char *dev_name,
1515 			     char **hostname, size_t maxnamlen,
1516 			     char **export_path, size_t maxpathlen)
1517 {
1518 	if (*dev_name == '[')
1519 		return nfs_parse_protected_hostname(dev_name,
1520 						    hostname, maxnamlen,
1521 						    export_path, maxpathlen);
1522 
1523 	return nfs_parse_simple_hostname(dev_name,
1524 					 hostname, maxnamlen,
1525 					 export_path, maxpathlen);
1526 }
1527 
1528 /*
1529  * Validate the NFS2/NFS3 mount data
1530  * - fills in the mount root filehandle
1531  *
1532  * For option strings, user space handles the following behaviors:
1533  *
1534  * + DNS: mapping server host name to IP address ("addr=" option)
1535  *
1536  * + failure mode: how to behave if a mount request can't be handled
1537  *   immediately ("fg/bg" option)
1538  *
1539  * + retry: how often to retry a mount request ("retry=" option)
1540  *
1541  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1542  *   mountproto=tcp after mountproto=udp, and so on
1543  */
1544 static int nfs_validate_mount_data(void *options,
1545 				   struct nfs_parsed_mount_data *args,
1546 				   struct nfs_fh *mntfh,
1547 				   const char *dev_name)
1548 {
1549 	struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1550 
1551 	if (data == NULL)
1552 		goto out_no_data;
1553 
1554 	args->flags		= (NFS_MOUNT_VER3 | NFS_MOUNT_TCP);
1555 	args->rsize		= NFS_MAX_FILE_IO_SIZE;
1556 	args->wsize		= NFS_MAX_FILE_IO_SIZE;
1557 	args->acregmin		= NFS_DEF_ACREGMIN;
1558 	args->acregmax		= NFS_DEF_ACREGMAX;
1559 	args->acdirmin		= NFS_DEF_ACDIRMIN;
1560 	args->acdirmax		= NFS_DEF_ACDIRMAX;
1561 	args->mount_server.port	= 0;	/* autobind unless user sets port */
1562 	args->nfs_server.port	= 0;	/* autobind unless user sets port */
1563 	args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1564 	args->auth_flavors[0]	= RPC_AUTH_UNIX;
1565 
1566 	switch (data->version) {
1567 	case 1:
1568 		data->namlen = 0;
1569 	case 2:
1570 		data->bsize = 0;
1571 	case 3:
1572 		if (data->flags & NFS_MOUNT_VER3)
1573 			goto out_no_v3;
1574 		data->root.size = NFS2_FHSIZE;
1575 		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1576 	case 4:
1577 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1578 			goto out_no_sec;
1579 	case 5:
1580 		memset(data->context, 0, sizeof(data->context));
1581 	case 6:
1582 		if (data->flags & NFS_MOUNT_VER3) {
1583 			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1584 				goto out_invalid_fh;
1585 			mntfh->size = data->root.size;
1586 		} else
1587 			mntfh->size = NFS2_FHSIZE;
1588 
1589 
1590 		memcpy(mntfh->data, data->root.data, mntfh->size);
1591 		if (mntfh->size < sizeof(mntfh->data))
1592 			memset(mntfh->data + mntfh->size, 0,
1593 			       sizeof(mntfh->data) - mntfh->size);
1594 
1595 		/*
1596 		 * Translate to nfs_parsed_mount_data, which nfs_fill_super
1597 		 * can deal with.
1598 		 */
1599 		args->flags		= data->flags & NFS_MOUNT_FLAGMASK;
1600 		args->rsize		= data->rsize;
1601 		args->wsize		= data->wsize;
1602 		args->timeo		= data->timeo;
1603 		args->retrans		= data->retrans;
1604 		args->acregmin		= data->acregmin;
1605 		args->acregmax		= data->acregmax;
1606 		args->acdirmin		= data->acdirmin;
1607 		args->acdirmax		= data->acdirmax;
1608 
1609 		memcpy(&args->nfs_server.address, &data->addr,
1610 		       sizeof(data->addr));
1611 		args->nfs_server.addrlen = sizeof(data->addr);
1612 		if (!nfs_verify_server_address((struct sockaddr *)
1613 						&args->nfs_server.address))
1614 			goto out_no_address;
1615 
1616 		if (!(data->flags & NFS_MOUNT_TCP))
1617 			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1618 		/* N.B. caller will free nfs_server.hostname in all cases */
1619 		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1620 		args->namlen		= data->namlen;
1621 		args->bsize		= data->bsize;
1622 
1623 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1624 			args->auth_flavors[0] = data->pseudoflavor;
1625 		if (!args->nfs_server.hostname)
1626 			goto out_nomem;
1627 
1628 		/*
1629 		 * The legacy version 6 binary mount data from userspace has a
1630 		 * field used only to transport selinux information into the
1631 		 * the kernel.  To continue to support that functionality we
1632 		 * have a touch of selinux knowledge here in the NFS code. The
1633 		 * userspace code converted context=blah to just blah so we are
1634 		 * converting back to the full string selinux understands.
1635 		 */
1636 		if (data->context[0]){
1637 #ifdef CONFIG_SECURITY_SELINUX
1638 			int rc;
1639 			char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1640 			if (!opts_str)
1641 				return -ENOMEM;
1642 			strcpy(opts_str, "context=");
1643 			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1644 			strcat(opts_str, &data->context[0]);
1645 			rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1646 			kfree(opts_str);
1647 			if (rc)
1648 				return rc;
1649 #else
1650 			return -EINVAL;
1651 #endif
1652 		}
1653 
1654 		break;
1655 	default: {
1656 		int status;
1657 
1658 		if (nfs_parse_mount_options((char *)options, args) == 0)
1659 			return -EINVAL;
1660 
1661 		if (!nfs_verify_server_address((struct sockaddr *)
1662 						&args->nfs_server.address))
1663 			goto out_no_address;
1664 
1665 		nfs_set_port((struct sockaddr *)&args->nfs_server.address,
1666 				args->nfs_server.port);
1667 
1668 		nfs_set_mount_transport_protocol(args);
1669 
1670 		status = nfs_parse_devname(dev_name,
1671 					   &args->nfs_server.hostname,
1672 					   PAGE_SIZE,
1673 					   &args->nfs_server.export_path,
1674 					   NFS_MAXPATHLEN);
1675 		if (!status)
1676 			status = nfs_try_mount(args, mntfh);
1677 
1678 		kfree(args->nfs_server.export_path);
1679 		args->nfs_server.export_path = NULL;
1680 
1681 		if (status)
1682 			return status;
1683 
1684 		break;
1685 		}
1686 	}
1687 
1688 #ifndef CONFIG_NFS_V3
1689 	if (args->flags & NFS_MOUNT_VER3)
1690 		goto out_v3_not_compiled;
1691 #endif /* !CONFIG_NFS_V3 */
1692 
1693 	return 0;
1694 
1695 out_no_data:
1696 	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1697 	return -EINVAL;
1698 
1699 out_no_v3:
1700 	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1701 		 data->version);
1702 	return -EINVAL;
1703 
1704 out_no_sec:
1705 	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1706 	return -EINVAL;
1707 
1708 #ifndef CONFIG_NFS_V3
1709 out_v3_not_compiled:
1710 	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1711 	return -EPROTONOSUPPORT;
1712 #endif /* !CONFIG_NFS_V3 */
1713 
1714 out_nomem:
1715 	dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
1716 	return -ENOMEM;
1717 
1718 out_no_address:
1719 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1720 	return -EINVAL;
1721 
1722 out_invalid_fh:
1723 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1724 	return -EINVAL;
1725 }
1726 
1727 static int
1728 nfs_compare_remount_data(struct nfs_server *nfss,
1729 			 struct nfs_parsed_mount_data *data)
1730 {
1731 	if (data->flags != nfss->flags ||
1732 	    data->rsize != nfss->rsize ||
1733 	    data->wsize != nfss->wsize ||
1734 	    data->retrans != nfss->client->cl_timeout->to_retries ||
1735 	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
1736 	    data->acregmin != nfss->acregmin / HZ ||
1737 	    data->acregmax != nfss->acregmax / HZ ||
1738 	    data->acdirmin != nfss->acdirmin / HZ ||
1739 	    data->acdirmax != nfss->acdirmax / HZ ||
1740 	    data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
1741 	    data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
1742 	    memcmp(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1743 		   data->nfs_server.addrlen) != 0)
1744 		return -EINVAL;
1745 
1746 	return 0;
1747 }
1748 
1749 static int
1750 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
1751 {
1752 	int error;
1753 	struct nfs_server *nfss = sb->s_fs_info;
1754 	struct nfs_parsed_mount_data *data;
1755 	struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
1756 	struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
1757 	u32 nfsvers = nfss->nfs_client->rpc_ops->version;
1758 
1759 	/*
1760 	 * Userspace mount programs that send binary options generally send
1761 	 * them populated with default values. We have no way to know which
1762 	 * ones were explicitly specified. Fall back to legacy behavior and
1763 	 * just return success.
1764 	 */
1765 	if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
1766 	    (nfsvers <= 3 && (!options || (options->version >= 1 &&
1767 					   options->version <= 6))))
1768 		return 0;
1769 
1770 	data = kzalloc(sizeof(*data), GFP_KERNEL);
1771 	if (data == NULL)
1772 		return -ENOMEM;
1773 
1774 	/* fill out struct with values from existing mount */
1775 	data->flags = nfss->flags;
1776 	data->rsize = nfss->rsize;
1777 	data->wsize = nfss->wsize;
1778 	data->retrans = nfss->client->cl_timeout->to_retries;
1779 	data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
1780 	data->acregmin = nfss->acregmin / HZ;
1781 	data->acregmax = nfss->acregmax / HZ;
1782 	data->acdirmin = nfss->acdirmin / HZ;
1783 	data->acdirmax = nfss->acdirmax / HZ;
1784 	data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
1785 	data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
1786 	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1787 		data->nfs_server.addrlen);
1788 
1789 	/* overwrite those values with any that were specified */
1790 	error = nfs_parse_mount_options((char *)options, data);
1791 	if (error < 0)
1792 		goto out;
1793 
1794 	/* compare new mount options with old ones */
1795 	error = nfs_compare_remount_data(nfss, data);
1796 out:
1797 	kfree(data);
1798 	return error;
1799 }
1800 
1801 /*
1802  * Initialise the common bits of the superblock
1803  */
1804 static inline void nfs_initialise_sb(struct super_block *sb)
1805 {
1806 	struct nfs_server *server = NFS_SB(sb);
1807 
1808 	sb->s_magic = NFS_SUPER_MAGIC;
1809 
1810 	/* We probably want something more informative here */
1811 	snprintf(sb->s_id, sizeof(sb->s_id),
1812 		 "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1813 
1814 	if (sb->s_blocksize == 0)
1815 		sb->s_blocksize = nfs_block_bits(server->wsize,
1816 						 &sb->s_blocksize_bits);
1817 
1818 	if (server->flags & NFS_MOUNT_NOAC)
1819 		sb->s_flags |= MS_SYNCHRONOUS;
1820 
1821 	nfs_super_set_maxbytes(sb, server->maxfilesize);
1822 }
1823 
1824 /*
1825  * Finish setting up an NFS2/3 superblock
1826  */
1827 static void nfs_fill_super(struct super_block *sb,
1828 			   struct nfs_parsed_mount_data *data)
1829 {
1830 	struct nfs_server *server = NFS_SB(sb);
1831 
1832 	sb->s_blocksize_bits = 0;
1833 	sb->s_blocksize = 0;
1834 	if (data->bsize)
1835 		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1836 
1837 	if (server->flags & NFS_MOUNT_VER3) {
1838 		/* The VFS shouldn't apply the umask to mode bits. We will do
1839 		 * so ourselves when necessary.
1840 		 */
1841 		sb->s_flags |= MS_POSIXACL;
1842 		sb->s_time_gran = 1;
1843 	}
1844 
1845 	sb->s_op = &nfs_sops;
1846  	nfs_initialise_sb(sb);
1847 }
1848 
1849 /*
1850  * Finish setting up a cloned NFS2/3 superblock
1851  */
1852 static void nfs_clone_super(struct super_block *sb,
1853 			    const struct super_block *old_sb)
1854 {
1855 	struct nfs_server *server = NFS_SB(sb);
1856 
1857 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1858 	sb->s_blocksize = old_sb->s_blocksize;
1859 	sb->s_maxbytes = old_sb->s_maxbytes;
1860 
1861 	if (server->flags & NFS_MOUNT_VER3) {
1862 		/* The VFS shouldn't apply the umask to mode bits. We will do
1863 		 * so ourselves when necessary.
1864 		 */
1865 		sb->s_flags |= MS_POSIXACL;
1866 		sb->s_time_gran = 1;
1867 	}
1868 
1869 	sb->s_op = old_sb->s_op;
1870  	nfs_initialise_sb(sb);
1871 }
1872 
1873 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1874 
1875 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1876 {
1877 	const struct nfs_server *a = s->s_fs_info;
1878 	const struct rpc_clnt *clnt_a = a->client;
1879 	const struct rpc_clnt *clnt_b = b->client;
1880 
1881 	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1882 		goto Ebusy;
1883 	if (a->nfs_client != b->nfs_client)
1884 		goto Ebusy;
1885 	if (a->flags != b->flags)
1886 		goto Ebusy;
1887 	if (a->wsize != b->wsize)
1888 		goto Ebusy;
1889 	if (a->rsize != b->rsize)
1890 		goto Ebusy;
1891 	if (a->acregmin != b->acregmin)
1892 		goto Ebusy;
1893 	if (a->acregmax != b->acregmax)
1894 		goto Ebusy;
1895 	if (a->acdirmin != b->acdirmin)
1896 		goto Ebusy;
1897 	if (a->acdirmax != b->acdirmax)
1898 		goto Ebusy;
1899 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1900 		goto Ebusy;
1901 	return 1;
1902 Ebusy:
1903 	return 0;
1904 }
1905 
1906 struct nfs_sb_mountdata {
1907 	struct nfs_server *server;
1908 	int mntflags;
1909 };
1910 
1911 static int nfs_set_super(struct super_block *s, void *data)
1912 {
1913 	struct nfs_sb_mountdata *sb_mntdata = data;
1914 	struct nfs_server *server = sb_mntdata->server;
1915 	int ret;
1916 
1917 	s->s_flags = sb_mntdata->mntflags;
1918 	s->s_fs_info = server;
1919 	ret = set_anon_super(s, server);
1920 	if (ret == 0)
1921 		server->s_dev = s->s_dev;
1922 	return ret;
1923 }
1924 
1925 static int nfs_compare_super_address(struct nfs_server *server1,
1926 				     struct nfs_server *server2)
1927 {
1928 	struct sockaddr *sap1, *sap2;
1929 
1930 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1931 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1932 
1933 	if (sap1->sa_family != sap2->sa_family)
1934 		return 0;
1935 
1936 	switch (sap1->sa_family) {
1937 	case AF_INET: {
1938 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1939 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1940 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1941 			return 0;
1942 		if (sin1->sin_port != sin2->sin_port)
1943 			return 0;
1944 		break;
1945 	}
1946 	case AF_INET6: {
1947 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1948 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1949 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1950 			return 0;
1951 		if (sin1->sin6_port != sin2->sin6_port)
1952 			return 0;
1953 		break;
1954 	}
1955 	default:
1956 		return 0;
1957 	}
1958 
1959 	return 1;
1960 }
1961 
1962 static int nfs_compare_super(struct super_block *sb, void *data)
1963 {
1964 	struct nfs_sb_mountdata *sb_mntdata = data;
1965 	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1966 	int mntflags = sb_mntdata->mntflags;
1967 
1968 	if (!nfs_compare_super_address(old, server))
1969 		return 0;
1970 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1971 	if (old->flags & NFS_MOUNT_UNSHARED)
1972 		return 0;
1973 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1974 		return 0;
1975 	return nfs_compare_mount_options(sb, server, mntflags);
1976 }
1977 
1978 static int nfs_bdi_register(struct nfs_server *server)
1979 {
1980 	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
1981 }
1982 
1983 static int nfs_get_sb(struct file_system_type *fs_type,
1984 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1985 {
1986 	struct nfs_server *server = NULL;
1987 	struct super_block *s;
1988 	struct nfs_parsed_mount_data *data;
1989 	struct nfs_fh *mntfh;
1990 	struct dentry *mntroot;
1991 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1992 	struct nfs_sb_mountdata sb_mntdata = {
1993 		.mntflags = flags,
1994 	};
1995 	int error = -ENOMEM;
1996 
1997 	data = kzalloc(sizeof(*data), GFP_KERNEL);
1998 	mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
1999 	if (data == NULL || mntfh == NULL)
2000 		goto out_free_fh;
2001 
2002 	security_init_mnt_opts(&data->lsm_opts);
2003 
2004 	/* Validate the mount data */
2005 	error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
2006 	if (error < 0)
2007 		goto out;
2008 
2009 	/* Get a volume representation */
2010 	server = nfs_create_server(data, mntfh);
2011 	if (IS_ERR(server)) {
2012 		error = PTR_ERR(server);
2013 		goto out;
2014 	}
2015 	sb_mntdata.server = server;
2016 
2017 	if (server->flags & NFS_MOUNT_UNSHARED)
2018 		compare_super = NULL;
2019 
2020 	/* Get a superblock - note that we may end up sharing one that already exists */
2021 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2022 	if (IS_ERR(s)) {
2023 		error = PTR_ERR(s);
2024 		goto out_err_nosb;
2025 	}
2026 
2027 	if (s->s_fs_info != server) {
2028 		nfs_free_server(server);
2029 		server = NULL;
2030 	} else {
2031 		error = nfs_bdi_register(server);
2032 		if (error)
2033 			goto error_splat_super;
2034 	}
2035 
2036 	if (!s->s_root) {
2037 		/* initial superblock/root creation */
2038 		nfs_fill_super(s, data);
2039 	}
2040 
2041 	mntroot = nfs_get_root(s, mntfh);
2042 	if (IS_ERR(mntroot)) {
2043 		error = PTR_ERR(mntroot);
2044 		goto error_splat_super;
2045 	}
2046 
2047 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2048 	if (error)
2049 		goto error_splat_root;
2050 
2051 	s->s_flags |= MS_ACTIVE;
2052 	mnt->mnt_sb = s;
2053 	mnt->mnt_root = mntroot;
2054 	error = 0;
2055 
2056 out:
2057 	kfree(data->nfs_server.hostname);
2058 	kfree(data->mount_server.hostname);
2059 	security_free_mnt_opts(&data->lsm_opts);
2060 out_free_fh:
2061 	kfree(mntfh);
2062 	kfree(data);
2063 	return error;
2064 
2065 out_err_nosb:
2066 	nfs_free_server(server);
2067 	goto out;
2068 
2069 error_splat_root:
2070 	dput(mntroot);
2071 error_splat_super:
2072 	up_write(&s->s_umount);
2073 	deactivate_super(s);
2074 	goto out;
2075 }
2076 
2077 /*
2078  * Destroy an NFS2/3 superblock
2079  */
2080 static void nfs_kill_super(struct super_block *s)
2081 {
2082 	struct nfs_server *server = NFS_SB(s);
2083 
2084 	bdi_unregister(&server->backing_dev_info);
2085 	kill_anon_super(s);
2086 	nfs_free_server(server);
2087 }
2088 
2089 /*
2090  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2091  */
2092 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
2093 			   const char *dev_name, void *raw_data,
2094 			   struct vfsmount *mnt)
2095 {
2096 	struct nfs_clone_mount *data = raw_data;
2097 	struct super_block *s;
2098 	struct nfs_server *server;
2099 	struct dentry *mntroot;
2100 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2101 	struct nfs_sb_mountdata sb_mntdata = {
2102 		.mntflags = flags,
2103 	};
2104 	int error;
2105 
2106 	dprintk("--> nfs_xdev_get_sb()\n");
2107 
2108 	/* create a new volume representation */
2109 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2110 	if (IS_ERR(server)) {
2111 		error = PTR_ERR(server);
2112 		goto out_err_noserver;
2113 	}
2114 	sb_mntdata.server = server;
2115 
2116 	if (server->flags & NFS_MOUNT_UNSHARED)
2117 		compare_super = NULL;
2118 
2119 	/* Get a superblock - note that we may end up sharing one that already exists */
2120 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2121 	if (IS_ERR(s)) {
2122 		error = PTR_ERR(s);
2123 		goto out_err_nosb;
2124 	}
2125 
2126 	if (s->s_fs_info != server) {
2127 		nfs_free_server(server);
2128 		server = NULL;
2129 	} else {
2130 		error = nfs_bdi_register(server);
2131 		if (error)
2132 			goto error_splat_super;
2133 	}
2134 
2135 	if (!s->s_root) {
2136 		/* initial superblock/root creation */
2137 		nfs_clone_super(s, data->sb);
2138 	}
2139 
2140 	mntroot = nfs_get_root(s, data->fh);
2141 	if (IS_ERR(mntroot)) {
2142 		error = PTR_ERR(mntroot);
2143 		goto error_splat_super;
2144 	}
2145 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2146 		dput(mntroot);
2147 		error = -ESTALE;
2148 		goto error_splat_super;
2149 	}
2150 
2151 	s->s_flags |= MS_ACTIVE;
2152 	mnt->mnt_sb = s;
2153 	mnt->mnt_root = mntroot;
2154 
2155 	/* clone any lsm security options from the parent to the new sb */
2156 	security_sb_clone_mnt_opts(data->sb, s);
2157 
2158 	dprintk("<-- nfs_xdev_get_sb() = 0\n");
2159 	return 0;
2160 
2161 out_err_nosb:
2162 	nfs_free_server(server);
2163 out_err_noserver:
2164 	dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
2165 	return error;
2166 
2167 error_splat_super:
2168 	up_write(&s->s_umount);
2169 	deactivate_super(s);
2170 	dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
2171 	return error;
2172 }
2173 
2174 #ifdef CONFIG_NFS_V4
2175 
2176 /*
2177  * Finish setting up a cloned NFS4 superblock
2178  */
2179 static void nfs4_clone_super(struct super_block *sb,
2180 			    const struct super_block *old_sb)
2181 {
2182 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2183 	sb->s_blocksize = old_sb->s_blocksize;
2184 	sb->s_maxbytes = old_sb->s_maxbytes;
2185 	sb->s_time_gran = 1;
2186 	sb->s_op = old_sb->s_op;
2187  	nfs_initialise_sb(sb);
2188 }
2189 
2190 /*
2191  * Set up an NFS4 superblock
2192  */
2193 static void nfs4_fill_super(struct super_block *sb)
2194 {
2195 	sb->s_time_gran = 1;
2196 	sb->s_op = &nfs4_sops;
2197 	nfs_initialise_sb(sb);
2198 }
2199 
2200 /*
2201  * Validate NFSv4 mount options
2202  */
2203 static int nfs4_validate_mount_data(void *options,
2204 				    struct nfs_parsed_mount_data *args,
2205 				    const char *dev_name)
2206 {
2207 	struct sockaddr_in *ap;
2208 	struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2209 	char *c;
2210 
2211 	if (data == NULL)
2212 		goto out_no_data;
2213 
2214 	args->rsize		= NFS_MAX_FILE_IO_SIZE;
2215 	args->wsize		= NFS_MAX_FILE_IO_SIZE;
2216 	args->acregmin		= NFS_DEF_ACREGMIN;
2217 	args->acregmax		= NFS_DEF_ACREGMAX;
2218 	args->acdirmin		= NFS_DEF_ACDIRMIN;
2219 	args->acdirmax		= NFS_DEF_ACDIRMAX;
2220 	args->nfs_server.port	= NFS_PORT; /* 2049 unless user set port= */
2221 	args->auth_flavors[0]	= RPC_AUTH_UNIX;
2222 	args->auth_flavor_len	= 0;
2223 
2224 	switch (data->version) {
2225 	case 1:
2226 		ap = (struct sockaddr_in *)&args->nfs_server.address;
2227 		if (data->host_addrlen > sizeof(args->nfs_server.address))
2228 			goto out_no_address;
2229 		if (data->host_addrlen == 0)
2230 			goto out_no_address;
2231 		args->nfs_server.addrlen = data->host_addrlen;
2232 		if (copy_from_user(ap, data->host_addr, data->host_addrlen))
2233 			return -EFAULT;
2234 		if (!nfs_verify_server_address((struct sockaddr *)
2235 						&args->nfs_server.address))
2236 			goto out_no_address;
2237 
2238 		if (data->auth_flavourlen) {
2239 			if (data->auth_flavourlen > 1)
2240 				goto out_inval_auth;
2241 			if (copy_from_user(&args->auth_flavors[0],
2242 					   data->auth_flavours,
2243 					   sizeof(args->auth_flavors[0])))
2244 				return -EFAULT;
2245 		}
2246 
2247 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2248 		if (IS_ERR(c))
2249 			return PTR_ERR(c);
2250 		args->nfs_server.hostname = c;
2251 
2252 		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2253 		if (IS_ERR(c))
2254 			return PTR_ERR(c);
2255 		args->nfs_server.export_path = c;
2256 		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2257 
2258 		c = strndup_user(data->client_addr.data, 16);
2259 		if (IS_ERR(c))
2260 			return PTR_ERR(c);
2261 		args->client_address = c;
2262 
2263 		/*
2264 		 * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2265 		 * can deal with.
2266 		 */
2267 
2268 		args->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
2269 		args->rsize	= data->rsize;
2270 		args->wsize	= data->wsize;
2271 		args->timeo	= data->timeo;
2272 		args->retrans	= data->retrans;
2273 		args->acregmin	= data->acregmin;
2274 		args->acregmax	= data->acregmax;
2275 		args->acdirmin	= data->acdirmin;
2276 		args->acdirmax	= data->acdirmax;
2277 		args->nfs_server.protocol = data->proto;
2278 		nfs_validate_transport_protocol(args);
2279 
2280 		break;
2281 	default: {
2282 		int status;
2283 
2284 		if (nfs_parse_mount_options((char *)options, args) == 0)
2285 			return -EINVAL;
2286 
2287 		if (!nfs_verify_server_address((struct sockaddr *)
2288 						&args->nfs_server.address))
2289 			return -EINVAL;
2290 
2291 		nfs_set_port((struct sockaddr *)&args->nfs_server.address,
2292 				args->nfs_server.port);
2293 
2294 		nfs_validate_transport_protocol(args);
2295 
2296 		if (args->auth_flavor_len > 1)
2297 			goto out_inval_auth;
2298 
2299 		if (args->client_address == NULL)
2300 			goto out_no_client_address;
2301 
2302 		status = nfs_parse_devname(dev_name,
2303 					   &args->nfs_server.hostname,
2304 					   NFS4_MAXNAMLEN,
2305 					   &args->nfs_server.export_path,
2306 					   NFS4_MAXPATHLEN);
2307 		if (status < 0)
2308 			return status;
2309 
2310 		break;
2311 		}
2312 	}
2313 
2314 	return 0;
2315 
2316 out_no_data:
2317 	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2318 	return -EINVAL;
2319 
2320 out_inval_auth:
2321 	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2322 		 data->auth_flavourlen);
2323 	return -EINVAL;
2324 
2325 out_no_address:
2326 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2327 	return -EINVAL;
2328 
2329 out_no_client_address:
2330 	dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
2331 	return -EINVAL;
2332 }
2333 
2334 /*
2335  * Get the superblock for an NFS4 mountpoint
2336  */
2337 static int nfs4_get_sb(struct file_system_type *fs_type,
2338 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2339 {
2340 	struct nfs_parsed_mount_data *data;
2341 	struct super_block *s;
2342 	struct nfs_server *server;
2343 	struct nfs_fh *mntfh;
2344 	struct dentry *mntroot;
2345 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2346 	struct nfs_sb_mountdata sb_mntdata = {
2347 		.mntflags = flags,
2348 	};
2349 	int error = -ENOMEM;
2350 
2351 	data = kzalloc(sizeof(*data), GFP_KERNEL);
2352 	mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
2353 	if (data == NULL || mntfh == NULL)
2354 		goto out_free_fh;
2355 
2356 	security_init_mnt_opts(&data->lsm_opts);
2357 
2358 	/* Validate the mount data */
2359 	error = nfs4_validate_mount_data(raw_data, data, dev_name);
2360 	if (error < 0)
2361 		goto out;
2362 
2363 	/* Get a volume representation */
2364 	server = nfs4_create_server(data, mntfh);
2365 	if (IS_ERR(server)) {
2366 		error = PTR_ERR(server);
2367 		goto out;
2368 	}
2369 	sb_mntdata.server = server;
2370 
2371 	if (server->flags & NFS4_MOUNT_UNSHARED)
2372 		compare_super = NULL;
2373 
2374 	/* Get a superblock - note that we may end up sharing one that already exists */
2375 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2376 	if (IS_ERR(s)) {
2377 		error = PTR_ERR(s);
2378 		goto out_free;
2379 	}
2380 
2381 	if (s->s_fs_info != server) {
2382 		nfs_free_server(server);
2383 		server = NULL;
2384 	} else {
2385 		error = nfs_bdi_register(server);
2386 		if (error)
2387 			goto error_splat_super;
2388 	}
2389 
2390 	if (!s->s_root) {
2391 		/* initial superblock/root creation */
2392 		nfs4_fill_super(s);
2393 	}
2394 
2395 	mntroot = nfs4_get_root(s, mntfh);
2396 	if (IS_ERR(mntroot)) {
2397 		error = PTR_ERR(mntroot);
2398 		goto error_splat_super;
2399 	}
2400 
2401 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2402 	if (error)
2403 		goto error_splat_root;
2404 
2405 	s->s_flags |= MS_ACTIVE;
2406 	mnt->mnt_sb = s;
2407 	mnt->mnt_root = mntroot;
2408 	error = 0;
2409 
2410 out:
2411 	kfree(data->client_address);
2412 	kfree(data->nfs_server.export_path);
2413 	kfree(data->nfs_server.hostname);
2414 	security_free_mnt_opts(&data->lsm_opts);
2415 out_free_fh:
2416 	kfree(mntfh);
2417 	kfree(data);
2418 	return error;
2419 
2420 out_free:
2421 	nfs_free_server(server);
2422 	goto out;
2423 
2424 error_splat_root:
2425 	dput(mntroot);
2426 error_splat_super:
2427 	up_write(&s->s_umount);
2428 	deactivate_super(s);
2429 	goto out;
2430 }
2431 
2432 static void nfs4_kill_super(struct super_block *sb)
2433 {
2434 	struct nfs_server *server = NFS_SB(sb);
2435 
2436 	nfs_super_return_all_delegations(sb);
2437 	kill_anon_super(sb);
2438 
2439 	nfs4_renewd_prepare_shutdown(server);
2440 	nfs_free_server(server);
2441 }
2442 
2443 /*
2444  * Clone an NFS4 server record on xdev traversal (FSID-change)
2445  */
2446 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
2447 			    const char *dev_name, void *raw_data,
2448 			    struct vfsmount *mnt)
2449 {
2450 	struct nfs_clone_mount *data = raw_data;
2451 	struct super_block *s;
2452 	struct nfs_server *server;
2453 	struct dentry *mntroot;
2454 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2455 	struct nfs_sb_mountdata sb_mntdata = {
2456 		.mntflags = flags,
2457 	};
2458 	int error;
2459 
2460 	dprintk("--> nfs4_xdev_get_sb()\n");
2461 
2462 	/* create a new volume representation */
2463 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2464 	if (IS_ERR(server)) {
2465 		error = PTR_ERR(server);
2466 		goto out_err_noserver;
2467 	}
2468 	sb_mntdata.server = server;
2469 
2470 	if (server->flags & NFS4_MOUNT_UNSHARED)
2471 		compare_super = NULL;
2472 
2473 	/* Get a superblock - note that we may end up sharing one that already exists */
2474 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2475 	if (IS_ERR(s)) {
2476 		error = PTR_ERR(s);
2477 		goto out_err_nosb;
2478 	}
2479 
2480 	if (s->s_fs_info != server) {
2481 		nfs_free_server(server);
2482 		server = NULL;
2483 	} else {
2484 		error = nfs_bdi_register(server);
2485 		if (error)
2486 			goto error_splat_super;
2487 	}
2488 
2489 	if (!s->s_root) {
2490 		/* initial superblock/root creation */
2491 		nfs4_clone_super(s, data->sb);
2492 	}
2493 
2494 	mntroot = nfs4_get_root(s, data->fh);
2495 	if (IS_ERR(mntroot)) {
2496 		error = PTR_ERR(mntroot);
2497 		goto error_splat_super;
2498 	}
2499 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2500 		dput(mntroot);
2501 		error = -ESTALE;
2502 		goto error_splat_super;
2503 	}
2504 
2505 	s->s_flags |= MS_ACTIVE;
2506 	mnt->mnt_sb = s;
2507 	mnt->mnt_root = mntroot;
2508 
2509 	security_sb_clone_mnt_opts(data->sb, s);
2510 
2511 	dprintk("<-- nfs4_xdev_get_sb() = 0\n");
2512 	return 0;
2513 
2514 out_err_nosb:
2515 	nfs_free_server(server);
2516 out_err_noserver:
2517 	dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
2518 	return error;
2519 
2520 error_splat_super:
2521 	up_write(&s->s_umount);
2522 	deactivate_super(s);
2523 	dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
2524 	return error;
2525 }
2526 
2527 /*
2528  * Create an NFS4 server record on referral traversal
2529  */
2530 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
2531 				const char *dev_name, void *raw_data,
2532 				struct vfsmount *mnt)
2533 {
2534 	struct nfs_clone_mount *data = raw_data;
2535 	struct super_block *s;
2536 	struct nfs_server *server;
2537 	struct dentry *mntroot;
2538 	struct nfs_fh mntfh;
2539 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2540 	struct nfs_sb_mountdata sb_mntdata = {
2541 		.mntflags = flags,
2542 	};
2543 	int error;
2544 
2545 	dprintk("--> nfs4_referral_get_sb()\n");
2546 
2547 	/* create a new volume representation */
2548 	server = nfs4_create_referral_server(data, &mntfh);
2549 	if (IS_ERR(server)) {
2550 		error = PTR_ERR(server);
2551 		goto out_err_noserver;
2552 	}
2553 	sb_mntdata.server = server;
2554 
2555 	if (server->flags & NFS4_MOUNT_UNSHARED)
2556 		compare_super = NULL;
2557 
2558 	/* Get a superblock - note that we may end up sharing one that already exists */
2559 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2560 	if (IS_ERR(s)) {
2561 		error = PTR_ERR(s);
2562 		goto out_err_nosb;
2563 	}
2564 
2565 	if (s->s_fs_info != server) {
2566 		nfs_free_server(server);
2567 		server = NULL;
2568 	} else {
2569 		error = nfs_bdi_register(server);
2570 		if (error)
2571 			goto error_splat_super;
2572 	}
2573 
2574 	if (!s->s_root) {
2575 		/* initial superblock/root creation */
2576 		nfs4_fill_super(s);
2577 	}
2578 
2579 	mntroot = nfs4_get_root(s, &mntfh);
2580 	if (IS_ERR(mntroot)) {
2581 		error = PTR_ERR(mntroot);
2582 		goto error_splat_super;
2583 	}
2584 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2585 		dput(mntroot);
2586 		error = -ESTALE;
2587 		goto error_splat_super;
2588 	}
2589 
2590 	s->s_flags |= MS_ACTIVE;
2591 	mnt->mnt_sb = s;
2592 	mnt->mnt_root = mntroot;
2593 
2594 	security_sb_clone_mnt_opts(data->sb, s);
2595 
2596 	dprintk("<-- nfs4_referral_get_sb() = 0\n");
2597 	return 0;
2598 
2599 out_err_nosb:
2600 	nfs_free_server(server);
2601 out_err_noserver:
2602 	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
2603 	return error;
2604 
2605 error_splat_super:
2606 	up_write(&s->s_umount);
2607 	deactivate_super(s);
2608 	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
2609 	return error;
2610 }
2611 
2612 #endif /* CONFIG_NFS_V4 */
2613